Automatic nut wrench



Nov. 3, 1931. J. v. LARSON- AUTOMATIC NUT WRENCH Filed March 26, 1931 JOHN l/mso/v,

teeth on the hub Patented Nov. 3, 1931 rrao STATES PATENT 'OFFIC JOHN v. Larson, 0:? ,cnrcneo, ILLmoIs AUTOMATIC NUT Wanner:

Application filed March 28, 1931. Serial No. 525,568.

This application embodies the same matter as abandoned application Serial No. 386,341 filed August 16, 1929..

This invention relates to'that type of autott mat-i0 nut wrenches in which the movement towards and holding engagement of the wrench jaws with the nut or like object to be manipulated is effected by an operative engagement between a plurality of gear portion of the operating wrench handle Wltll complementary gear teeth on the base of the movable wrench jaw, with said movable wrench jaw having sliding movement in the main wrench head or body and of which the stationary wrench jaw forms a part,'and in which wrench head the operating handle is pivotally mounted.

And this improvement has for its object To provide in the above described type of automatic nut wrench, a structural formation and combination of parts 1n the gearing connection between the operating handle and the movable wrench jaw whereby an extended range of adjustments in the movable wrench jaw is obtained to engage and effectively manipulate three standard sizes of nuts in a given size of wrench, and so that two sizes of the present wrench structure will adequately meet requirements of the general user in the manipulation of the different sizes of nuts generally met with. In addition said formation and combination is intended to aiford a maximum holding action on faces of the nut that is being manipulated with an entire prevention of any tendency to an automatic opening movement of the jaws, due to a variance in the leverage of the corners of the nut and the leverage exerted by the wrench handle, in that with a less leverage exerted by'the wrench handle,

the jaws would automatically open under the greater leverage stress of the corners of the nut. under manipulation, all as will hereinafter more fully appear.

In the accompanying drawings:

Fig. 1 is a sectional elevation of an automatic nut wrench having this invention applied.

Figs. 2 3 and 4 are enlarged detail elevations, s owing the relative position of the gearing elements of the wrench in engagement with three progressive sizes of standar nuts. 1

Like reference numerals indicate like parts in different views.

In the automatic nut wrench construction used to illustrate this invention, the wrench head or body 1 comprises a pair of cheek plates rigidly connected together in spaced relation by an integral corner portion constituting the fixed jaw 2 of the wrench with the space between said cheek plates adapted to receive-and provide guiding engagement for base portion 3 of themovable jaw 4 of the wrench. In addition said space is adapted to receive hub portion 5 of the operating handle '6, which is pivotally attached in position by the usual transverse pivot pin 7. And as usual in this type of wrench operative connection between the handle hub 5' and the base portion 3 of the movable jaw 4 is attained by interengaging gear teeth formations on the perimeter of the handle hub 5 and on the base portion 3 of the movable wrench jaw 4.

In connection with an automatic nut wrench construction above described, the material feature of this invention comprises a specific formation and relative arrangement of the series of gear teeth on the handle hub 5 and of the corresponding'gear teeth on the base portion 3 of the movable wrench jaw 4, as follows The specific formation and arrangement of the gear teeth on the handle hub 5 comprlses three gear teeth 8, 8 and 8", spaced to effect serial movements of the movable wrench jaw 4 with relation to the stationary wrench jaw 2, to a series of spaced adjustments corresponding with a progressive range in sizes of hexagon nuts of the standard size and which the wrench is intended to manipulate, and so that the pitch line point of engagement between an individual gear tooth of the handle hub 5 and that of the corresponding individualtooth 9,9 or 9" of the base portion 3 'of themo'vable wrench jaw will be on a line of holding stress in an engagement of the wrench jaws with a hexagon nut of a required size during its manipulation by the wrench. In addition to and in combination with the above described special construction, the pitch line of the series of gear teeth of the handle hub 5 will increase in distance from the pivot axis of the wrench handle 6 so that the distance of the pitch line engagement of each gear tooth from said axis is a fraction less than the length of the face of the nut which is to be engaged. The function resulting from such construction is a prevention of an automatic opening of the wrench under a superior leverage of a corner of the nut when the same has greater leverage than the leverage existing at the pitch line engagement of a pair of the individual pair of opposed gear teeth that are in position of actual use. In-

vcidently, the pluralities of said gear teeth will have progressive increase in size so as to provide ample resistance to breakage as the operating stress required, increases with an increase in the size of the nuts the wrench is adapted to handle.

With the specific structural formation and combination of parts above described, it has been found from extended practical tests that a convenient and eminently practical automatic nut wrench is provided, in which a range of three sizes of hexagonal nuts can be manipulated without any liability to breakage of the operating parts and with entire prevention of an automatic opening of the wrench jaws and release of their holding engagement with a nut being manipulated, which has been a serious defect in automatic nut wrenches of the present type, heretofore introduced from time to time in the wrench market.

lVith the capability of manipulating three sizes of hexagonal nuts as above set forth, it is possible to produce and supply the ordinary requirements of the market with two sizes of the wrench, with the smaller size handling nuts ranging from nine-thirty-seconds t0 fifteen-sixteenths of an' inch, and the larger size, nuts ranging from nine-sixteenths to one and one-half inches.

Having thus fully described my invention, what I claim as new, is

1. An automatic nut wrench comprising a main body carrying a fixed jaw, a movable jaw the base of which has sliding engagement in said main body, an operating handle having a journal hub pivotally mounted in said main body, and interengaging teeth on the base of said movable jaw and on the perimeter of the journal hub of the handle, with the pitch line contact between each individual pair of teeth when in action on a line parallel with the faces of the wrench jaws and cutting the pivot axis of the operating handle and with the distance of such pitch line contact ofeach pair of teeth from said pivot axis of the operating handle a fraction less than the distance across the face of a nut of proper size to fit between the wrench jaws at such position of the parts.

2. In an automatic nut wrench comprising a main body carrying a fixed jaw, a movable jaw the base of which has sliding engagement in said main body, an operating handle having a journal hub pivotally mounted in said main body, and interengaging gear teeth on the base of said movable jaw and on the perimeter of the journal hub of the handle, with the gear teeth of said parts progressive ly increasing in size with the size of the nuts being manipulated, and with the pitch line contact between each individual pair of teeth when in action on a line parallel with the faces of the wrench jaws and cutting the pivot axis of the operating handle and with the distance of such pitch line contact of each pair of teeth from said pivot axis of the operating handle a fraction less than the distance across a face of a nut of the proper size to fit between the wrench jaws at such position of the parts.

In testimony whereof I hereunto affix my signature. 4

JOHN V. LARSON. 

